Portable soft-sided and rigid-sided containers are available in numerous sizes for various uses. For instance, there are containers which are used as coolers that are specifically sized for an individual lunch, and coolers that are capable of holding food and beverages for a large family. A person thus typically owns many differently-sized coolers for different situations. Aside from the expense of purchasing multiple coolers, the coolers require substantial storage space while not in use. Although soft-sided coolers may be collapsed and stored in a relatively small space, soft-sided coolers are not generally available in large-family sizes because the soft, flexible walls cause such a cooler to be difficult to carry when fully loaded with beverages and ice. Large rigid-sided coolers are ideal in these situations because they do not sag or bend when fully loaded. Such coolers are, however, difficult to store because of their overall volume. It is thus desirable to provide a cooler that has the strength and rigidity of a rigid-sided cooler while being collapsible so that it is easy to store.
Rigid-sided coolers are typically fabricated from plastic or metals such that they are durable and prevent items inside the cooler from being damaged if another article impacts the cooler or if an article is placed on top of the cooler. One problem with a large, rigid-sided cooler is that the interior volume that must be cooled is constant. Thus, even if only a few small items are in the cooler, the coolant, which is typically ice, must maintain a relatively large volume of air cool to cool these items. Thus, it is desirable to provide a cooler that may be configured to adjust the interior volume that must be kept cool by the coolant.